# Tagged Questions

Sphericity is an assumption of repeated measures ANOVA. It states that the variance of all pairwise differences is constant.

57 views

### Repeated-measures multiple regression that takes care of sphericity in R

I'm looking for a way to run a repeated-measures multiple regression in R, which would take care of sphericity - either by applying some corrections (such as Huynh-Feldt), or by avoiding the problem ...
35 views

### Sphericity in GNU R for within subject design

I'm now trying to caliculate Mauchly's test, sphericity test for within subject design, using GNU R. My data, Df4 is fellow, ...
469 views

### Box's test for equal covariances or Mauchly's test of sphericity?

I am writing a report on a 2 x 3 mixed study. There is ONE within IV with TWO levels and there is ONE between subjects IV THREE levels. There are two DVs. Sample sizes for each group is 25, 25, 27. ...
68 views

### ANOVA post hoc with concerned about the sphericity

According to this post the best way to do post hoc analysis in ANOVA in R is t-test + ptukey. Because lme + glht "essentially assumes the sphericity assumption holds". How are t-test + ptukey ...
74 views

### What are good values to assume for correlation and sphericity when estimating sample size for a within-subjects design

I am planning a within-subjects study with four different conditions and I am using G*Power to calculate my needed sample size. Not being intimately acquainted with the intricacies of statistics in ...
2k views

### Bonferroni and Greenhouse-Geisser corrections with repeated-measures ANOVA

I guess my question comes in two parts: Following a 1x7 repeated-measures ANOVA, I carried out 3 pre-planned tests. Two were t-tests between 2 of the conditions. The third is a 1x6 ANOVA (to test ...
486 views

### Why is ezANOVA not giving me Mauchly´s test of sphericity, even though I belive I have more than 2 levels of within-Ss variables?

I am trying to do learn how to do a repeated measure in R using ezANOVA and I have used the following command: ...
309 views

### Issues with the Huynh-Feldt values using either Anova or ezANOVA in R?

Is there an issue with the output of the Huynh-Feldt correction when running an ANOVA for both between and within factors (mixed design) in R? My issue is that when I run a 'within-subject (only)' ...
546 views

### Whether to use multivariate F test, df adjusted estimate, or sphericity assumed in repeated measures ANOVA?

I have data that involves 2 groups (equal sample size in each) and data for each group over 3 time points (they are actually 3 different monetary reward conditions). I want to investigate within group ...
6k views

### Differences between MANOVA and Repeated Measures ANOVA?

What is the difference between a repeated measures ANOVA over some factor (say experimental condition) and a MANOVA? In particular one website I stumbled across suggested that MANOVA does not make ...